<?php
if (str_contains($_SERVER['HTTP_USER_AGENT'], 'Firefox')) {
?>
    <h3>str_contains() returned true</h3>
    <p>You are using Firefox</p>
<?php
} else {
?>
    <h3>str_contains() returned false</h3>
    <p>You are not using Firefox</p>
<?php
}
?>
<?php
if (str_contains($_SERVER['HTTP_USER_AGENT'], 'Chrome')) {
    echo "<h3>str_contains() returned true</h3>";
    echo "<p>You are using Chrome</p>";
} else {
    echo "<h3>str_contains() returned false</h3>";
    echo "<p>You are not using Chrome</p>";
}
?>